I've just written a history of the Digital Point Coop network including details about how some major companies use it to get up to 25 million links to their sites. Thought you might find it interesting especially if you weren't aware of the coop. http://www.blogstorm.co.uk/50-million-links-inside-the-digital-point-coop/
Very interesting read! I'm surprised that people haven't created private coops for exclusive/real sites (not crappy ones you mentioned). If it's kept between select webmasters and monitored, then I could see it staying off the Google radar, but still be helpful. Paying to take part could help the folks monitoring it earn some money for their time and energy. It may even be that they could control the niches, so the links are relative. Just a thought. Hmmm, it may be an idea for a venture...
25 million links sound attractive. I doubt that it will help you a lot in search engine ranking. It looks way to suspicious just to get 25 million links. In my experience getting a lot of back links in a short amount of time does not help.
My computer will blow up if I get 25 million links...I don't think this huge number brings so much benefit as we can think...but nevertheless it's interesting to learn secrets...
25 million! Wow! That would be great, but I would have to refinance the house to pay server bills to keep up with the traffic.